The present invention relates to couplers for use in transmitting intrinsically safe high frequency signals into hazardous areas, such as for use through the wall of a hazardous area enclosure.
In the prior art, the couplers that have been used for transmitting intrinsically safe signals into hazardous areas have used a Zener diode array, which is suitable for transmitting DC signals, but which has a high capacitance, on the order of nanofarads, which results in the circuit shunting alternating current signals to ground. This prevents those couplers from being able to be used to transmit intrinsically safe alternating current signals, and in particular high frequency signals such as Ethernet signals.